Study On The Combination Of Sedimentation With Coagulation+SBR Treating Wastewater Of Recycled Paper

One of paper plant in Jiangxi province uses waste papers for making pulp. The productions contain iridescent papers, color photo papers, decorative art papers, and so on. The course of production has a large quantity of wastewater. The constituents of the wastewater are complicated, and change frequently. The combination of coagulating sedimentation+SBR is used to dispose the wastewater. Under the controls of the addition of medicine and reaction time, the most of CODcr which in the pulping wastewater is removed. So the wastewater for SBR is in a low concentration. After coagulating sedimentation and aerobic treatment, the wastewater can reach the discharge standard of water pollutants for pulp and paper industry (GB3544-2008) table2.Through experiments, the thesis analyzes the principle of coagulating sedimentation, defines the preferred parameters. The start of SBR process and the operation conditions were also studied in this paper.(1) The wastewater contains two parts, one is pulping wastewater and another is water for paper-making. The water for paper-making pumps into the adjusting tank directly, the concentration of CODcr is between150and250mg/L, the average is200mg/L, the color of it is about150; the concentration of CODcr of the pulping wastewater is between1500mg/L and2500mg/L,the average is about1800mg/L,the color of it is350more or less. After the process of sedimentation with coagulation, the concentration of the pulping wastewater is800more or less, the color of the wastewater is about100. The remove rate is between45%and60%. Two parts of wastewater are pumped into the catches, the concentration of them are250to400mg/L.(2) Through the experiments, the paper define the preferred parameters for coagulating sedimentation:the dosage of coagulate flocculating agent is: PAM=2mg/L, PAC=500mg/L,reaction time is5min, under this condition the average CODcr removal efficiency remain about50%, and the average color remove rate is more than70%. (3) The system of SBR is made up of four reactors, the process of reactors is influent, aeration, sedimentation, drainage, rest. They work one by one. It overcome the limit of SBR, so it can work continuously.(4) Through investigating the effect elements in the start-up and run of SBR, the paper analyzes the start-up fashion and process and studies the effects of aeration time and temperature towards CODcr removal efficiency, respectively, then makes sure the cycle of SBR:influent time is2hour, aeration period is5.5hours (including influent time), sedimentation time is1hour, effluent time and detention time is1.5hour in total.(5) The total removed rate of CODcr reaches96%, and the various index accords with the Discharge standard of water pollutants for pulp and paper industry (GB3544-2008) table2.